You definitely incorporated the response to your previous questions, such as:
- Extract code into functions.
- Always indent with 4 spaces.
- Process input immediately instead of storing all input data and results in lists.
There is still too little (horizontal) whitespace, I suggest to check
your code against the PEP8 coding style,
for example at PEP8 online.
Also function and variable names should be
snake_case according to PEP8.
- Variable names:
T is too short and non-descriptive,
would be better.
pair is better named
- There is no need to pre-assign
The value of the iterator variable
i in the main loop is not needed,
a common convention is use
for _ in range(T):
Negation as in
-1*l[i] can be simplified to
When printing the result list
print(" ".join(str(x) for x in pair))
you can use
map instead, as you already do when reading the input:
print(" ".join(map(str, pair)))
Improving the performance:
Your algorithm has two nested loops traversing through the list, i.e. the
time complexity is \$ O(n^2) \$ as a function of the list length.
This can be improved by sorting the list first. One option would be to sort
the numbers in increasing order, e.g.
-3 -1 1 2 3 6
for the first test case, and then traverse the list from both ends to find
pairs. The time complexity is \$ O(n \log n) \$ for the sorting, and
\$ O(n) \$ for the traversal, so this would be faster for large input.
Another option is to sort the number in increasing absolute value, e.g.
-3 3 -1 1 2 6
Again a linear sweep of the sorted list is now sufficient to find matching pairs,
which are now consecutive entries.
Here is a possible implementation of the second approach:
numbers.sort(key=lambda x: x + 0.5 if x >= 0 else -x)
pairs = 
for pair in [(x, y) for x, y in zip(numbers, numbers[1:]) if x == -y]:
sort() with a custom key. This relies on the given fact that the numbers are
zip and list comprehension to enumerate pairs of consecutive list entries.